The present invention relates to splicing sheet material and has particular, but not exclusive, application to splicing paper, especially for use in the manufacture of corrugated board.
At the present time the paper feed into corrugating machinery is from reels of, for example 2 to 3 tons weight and in order to maintain continuity of feed two special arrangements have been devised to splice the end of an exhausting reel to the start of a replacement reel. In one commonly adopted arrangement (the so-called "flying splice"), the peripheral speed of a replacement reel is brought up to the speed of the paper being fed from the exhausting reel and the splice effected when the said speeds are substantially equal. In the other commonly adopted arrangement (the so-called stationary splice), the inlet path followed by the paper feed is variable in length so that paper at commencement of said path can be momentarily reduced to a stationary state without varying the speed of paper at the termination of the path. Usually, said path is of a zig-zag configuration with the apices defined by idler rollers arranged in two relatively movable sets to vary the length of the inter-apices sections of the path.
Neither of the said arrangements is satisfactory in that it involves costly equipment and/or requires substantial operator skill to ensure a good splice. It is an object of this invention to provide a relatively inexpensive arrangement suitable for splicing paper for feeding to corrugating machinery which is operable reliably by relatively unskilled operatives.
According to the present invention, there is provided a method of splicing stationary sheet material to moving sheet material which comprises providing on a portion of a face of the stationary sheet material adhesive means for adhering said sheet materials together, aligning said portion in opposed relationship with the moving sheet material at a position along the path thereof, bringing the said sheet materials into frictional engagement so that the moving sheet material drives the previously stationary sheet material and pressing the said sheet materials together downstream of said position to sandwich the adhesive means between the sheet materials.
The method of the invention has particular use in splicing together webs of paper, especially for use in corrugating machinery, where the stationary web is stored on a replacement reel and the moving web is being drawn from an exhausting reel. In the corrugating application the replacement reel weighs as much as 3 tons and it has previously been assumed that a splice could not be made between a moving web portion and a stationary web end from the replacement reel. The present invention permits such a splice to be readily made with the moving web travelling at a speed of up to 25 meters per minute. If desired or in some cases necessary, the stationary reel can be given an initial spin simultaneously with the frictional engagement of the webs to overcome or at least reduce the inertia of the reel to rotation in response to movement of the web thereof. Other means of reducing the strain upon the stationary web upon commencement of movement thereof can alternatively or additionally be provided. For example, a path of variable length can be provided between the stationary reel and the splice position in similar manner to that used in stationary splicing as described above.
It will be appreciated that when reference is made in this specification to the "stationary" sheet material etc., that material etc. which was stationary at commencement of the splicing operation is meant although the material etc. may be moving at the time to which the reference refers.
The method can be used to under or over splice as required and when consecutive splicing operations are carried out under splicing can alternate with over splicing.
It is preferred that cutting means are operated simultaneously with frictional engagement of the sheet materials to sever the moving sheet upstream of the position of such engagement.
Suitably, the sheet materials are frictionally engaged by pressing them together in the nip between two relatively movable idler-rollers. The means moving said rollers can also serve to operate the cutting means if present. The means pressing the sheet materials together to sandwich the adhesive means between them can also comprise the nip between two idler rollers which can be in fixed spatial relationship. It is presently preferred that the adhesive means is double sided adhesive tape, which tape is known for its use in conventional flying and stationary splicing. However, other adhesive means such as one sided adhesive tape and liquid adhesives or the like may also be employed.
The invention also provides apparatus for carrying out the method of the present invention, which apparatus comprises locating means for aligning the said portion of the stationary sheet material in opposed relationship with the moving sheet material at a position along the path thereof; drive means for bringing the said sheet materials into frictional engagement so that the moving sheet material drives the previously stationary sheet material; and pressure means located downstream of said position to sandwich the adhesive means between the sheet materials.
Preferably, the drive means and pressure means are idler rollers as referred to above with reference to the method of the invention. It is also preferred that cutting means are provided upstream of the splicing position to sever the moving sheet and that said means is operated simultaneously with the drive means when the latter brings the sheet materials into frictional engagement. Usually, the drive means will be upstream of the splicing position and the cutting means upstream of the drive means.
The locating means in the case of apparatus adapted for oversplicing can comprise a stationary guideplate preventing upward movement of the stationary sheet material during the splicing operation. In the case of apparatus adapted for under splicing, said means can include a support plate for supporting the stationary sheet material below the moving sheet material. Suitably, said plate is pivotally mounted for movement to an inoperative attitude to facilitate, for example, cutting of the stationary sheet material to a desired length and/or location of the adhesive means on said material.
The splicing apparatus and method is of relatively simple and inexpensive construction so as to avoid the use of highly skilled maintenance personnel. It is relatively compact and may be readily incorporated in existing paper sheet corrugating installations without requiring expensive modifications or additional equipment. The apparatus is pneumatically operated by standard factory compressed air supply and only two manually operable push button type electrical controls are utilized, one for slow-down of the corrugator apparatus and the other for initiating operation of the splicer apparatus. The actual operation of the apparatus is fully pneumatic without use of electric motors and electronic control circuits. Thus, the splicer apparatus is easy to operate and does not require a highly skilled operator. The splice preparation procedure is relatively simple and straight line threading is employed to reduce preparation time. The splicing apparatus may be operated automatically or remotely at a central control station. The apparatus has the additional advantages of enabling consistent good splices with minimum waste. The length of the tail on the depleting roll may consistently be kept at a length of from 8 to 10 inches so as to enable each paper roll to be substantially completely utilized. The apparatus requires minimal maintenance involving only lubrication and cleaning. In addition, the knife blade assembly comprises a series of individual blades of new design for maximum cutting efficiency and easy individual blade replacement.